The follow-up to 2011's Rise of the Planet of the Apes, opening Friday, thrusts viewers into what seems to be an ape-only world led by alpha ape Caesar.

"In my fantasy, this is like The Godfather of the ape world, with this civilization and Caesar as the Don Corleone of the apes," says director Matt Reeves. "It's about establishing this world where the apes are central."

It required great human performances from the core actors, wearing motion-capture suits to play primates onscreen. Andy Serkis returns as Caesar after his widely acclaimed performance in Rise, and Karin Konoval is back as the orangutan Maurice.

Former Cirque du Soleil performer Terry Notary plays Rocket and was the primate-movement choreographer -- a position so key that Reeves involved him in casting decisions.

The actors and five parkour expert stuntmen honed their primate technique in a four-week intensive training session led by Notary. Serkis then joined for three days of pure group ape role-playing before shooting.

"We were not even doing scenes from the movie," Reeves says. "It was improvisation of an ape day-in-the-life, seeing what this kingdom would look like."

Filming in Vancouver forests and sweltering New Orleans presented challenges in the motion-capture suits, which include helmets and facial cameras to record every expression. Most of the time, actors were able to lock into character despite the odd-looking outfits. "But there was one moment in the humidity of New Orleans that Terry and I just went into giggles. It was hard to keep it inside," Serkis says.

One impressive scene features 1,000 apes, many on horseback, outside a human compound. But all the ape sounds made the real horses skittish, so "the scene was really 10 guys in suits on stepladders. It looked really cheesy and cheap," Reeves says.

Notary and the stuntmen in motion-capture suites completed the ape tableau, playing each primate background character for the scene to make it appear to be an impressive army. "I literally played hundreds of characters in that scene," Notary says.

Then the New Zealand-based visual-effects company Weta Digital painstakingly completed the detailed apes seen onscreen.

"It takes so long to create one ape shot," Reeves says. "But when those first shots started coming in, you realize this movie was going to be something special."